Molecular alterations of Ras‐Raf‐mitogen‐activated protein kinase and phosphatidylinositol 3‐kinase‐Akt signaling pathways in colorectal cancers from a tertiary hospital at Kuala Lumpur,Malaysia

Molecular alterations in KRAS, BRAF, PIK3CA, and PTEN have been implicated in designing targeted therapy for colorectal cancer (CRC). The present study aimed to determine the status of these molecular alterations in Malaysian CRCs as such data are not available in the literature. We investigated the mutations of KRAS, BRAF, and PTEN, the gene amplification of PIK3CA, and the protein expression of PTEN and phosphatidylinositol 3‐kinase (PI3K) catalytic subunit (p110α) by direct DNA sequencing, quantitative real‐time PCR, and immunohistochemistry, respectively, in 49 CRC samples. The frequency of KRAS (codons 12, 13, and 61), BRAF (V600E), and PTEN mutations, and PIK3CA amplification was 25.0% (11/44), 2.3% (1/43), 0.0% (0/43), and 76.7% (33/43), respectively. Immunohistochemical staining demonstrated loss of PTEN protein in 54.5% (24/44) of CRCs and no significant difference in PI3K p110α expression between CRCs and the adjacent normal colonic mucosa (p = 0.380). PIK3CA amplification was not associated with PI3K p110α expression level, but associated with male cases (100% of male cases vs 56% of female cases harbored amplified PIK3CA, p = 0.002). PI3K p110α expression was significantly higher (p = 0.041) in poorly/moderately differentiated carcinoma compared with well‐differentiated carcinoma. KRAS mutation, PIK3CA amplification, PTEN loss, and PI3K p110α expression did not correlate with Akt phosphorylation or Ki‐67 expression. KRAS mutation, PIK3CA amplification, and PTEN loss were not mutually exclusive. This is the first report on CRC in Malaysia showing comparable frequency of KRAS mutation and PTEN loss, lower BRAF mutation rate, higher PIK3CA amplification frequency, and rare PTEN mutation, as compared with published reports.     

Refinement and delineation of the breakpoint regions of a chromosome 1;22 translocation in a patient with Costello syndrome*

Altered plasma levels of lipids and lipoproteins, obesity, hypertension, and diabetes are major risk factors for atherosclerotic cardiovascular disease. To identify genes that affect these traits and disorders, we looked for association between markers in candidate genes (apolipoprotein AII (apo AII), apolipoprotein AI‐CIII‐AIV gene cluster (apo AI‐CIII‐AIV), apolipoprotein E (apo E), cholesteryl ester transfer protein (CETP), cholesterol 7α‐hydroxylase (CYP7a), hepatic lipase (HL), and microsomal triglyceride transfer protein (MTP)) and known risk factors (triglycerides (Tg), total cholesterol (TC), apolipoprotein AI (apo AI), apolipoprotein AII (apo AII), apolipoprotein B (apo B), body mass index (BMI), blood pressure (BP), leptin, and fasting blood sugar (FBS) levels.) A total of 1,102 individuals from the Pacific island of Kosrae were genotyped for the following markers: Apo AII/MspI, Apo CIII/SstI, Apo AI/XmnI, Apo E/HhaI, CETP/TaqIB, CYP7a/BsaI, HL/DraI, and MTP/HhpI. After testing for population stratification, family‐based association analysis was carried out. Novel associations found were: 1) the apo AII/MspI with apo AI and BP levels, 2) the CYP7a/BsaI with apo AI and BMI levels. We also confirmed the following associations: 1) the apo AII/MspI with Tg level; 2) the apo CIII/SstI with Tg, TC, and apo B levels; 3) the Apo E/HhaI E2, E3, and E4 alleles with TC, apo AI, and apo B levels; and 4) the CETP/TaqIB with apo AI level. We further confirmed the connection between the apo AII gene and Tg level by a nonparametric linkage analysis. We therefore conclude that many of these candidate genes may play a significant role in susceptibility to heart disease. © 2002 Wiley‐Liss, Inc.     

Human native endocarditis caused by Streptococcus canis—a case report

We report a very rare case of Streptococcus canis native infective endocarditis in a 73‐year‐old woman living in close contact with her dog. Her echocardiography showed large calcifications in the mitral annulus, massive regurgitation below the posterior leaflet, and adjacent vegetation. Blood culture was positive for Streptococcus Lancefield group G. A coronary artery bypass and mitral valve replacement had to be done. Streptococcus canis was detected in a heart valve using a broad range PCR followed by 16S rRNA and confirmed by tuf gene sequencing, while tissue culture remained negative. The patient was not bitten by her dog nor did she have comorbidities or skin ulcers. She fully recovered.     

Presence of arginine catabolic mobile element among community‐acquired meticillin‐resistant staphylococcus aureus is linked to a specific genetic background

The prevalence of arginine catabolic mobile element (ACME) among diverse and heterogeneous community‐associated methicillin‐resistant Staphylococcus aureus community‐associated Methicillin‐resistant S. aureus (CA‐MRSA) (n = 114) in a low‐endemic area, i.e. Sweden, was investigated. Among the CA‐MRSA, represented by 47 different spa types, ACME was only found in 10 isolates with a common genetic background [t008, SCCmec type IV, Panton‐Valentine leukocidin (PVL) positive, and indistinguishable or closely related pulsed‐field gel electrophoresis (PFGE)‐patterns] corresponding to USA300. This strain does not seem to be established in our area as most of the patients contracted the CA‐MRSA abroad. Presence of ACME does not seem to be associated with colonization, long‐term carriership, or intra‐familiar transmission in a higher extent than CA‐MRSA in general.     

Exon‐Specific U1s Correct SPINK5 Exon 11 Skipping Caused by a Synonymous Substitution that Affects a Bifunctional Splicing Regulatory Element

The c.891C>T synonymous transition in SPINK5 induces exon 11 (E11) skipping and causes Netherton syndrome (NS). Using a specific RNA–protein interaction assay followed by mass spectrometry analysis along with silencing and overexpression of splicing factors, we showed that this mutation affects an exonic bifunctional splicing regulatory element composed by two partially overlapping silencer and enhancer sequences, recognized by hnRNPA1 and Tra2β splicing factors, respectively. The C‐to‐T substitution concomitantly increases hnRNPA1 and weakens Tra2β‐binding sites, leading to pathological E11 skipping. In hybrid minigenes, exon‐specific U1 small nuclear RNAs (ExSpe U1s) that target by complementarity intronic sequences downstream of the donor splice site rescued the E11 skipping defect caused by the c.891C>T mutation. ExSpe U1 lentiviral‐mediated transduction of primary NS keratinocytes from a patient bearing the mutation recovered the correct full‐length SPINK5 mRNA and the corresponding functional lympho‐epithelial Kazal‐type related inhibitor protein in a dose‐dependent manner. This study documents the reliability of a mutation‐specific, ExSpe U1‐based, splicing therapy for a relatively large subset of European NS patients. Usage of ExSpe U1 may represent a general approach for correction of splicing defects affecting skin disease genes.     

Survival in the environment is a possible key factor for the expansion of Escherichia coli strains producing extended‐spectrum β‐lactamases

Acquired resistance to cephalosporins in Enterobacteriaceae is a global problem. After an outbreak at Uppsala University Hospital of extended‐spectrum β‐lactamase (ESBL)‐positive Klebsiella pneumoniae producing CTX‐M‐15, there was a shift from AmpC to ESBL production among Escherichia coli isolates. To explore the basis for this epidemiological shift, 46 E. coli isolates (ESBLs, n = 23; AmpC, n = 23) were characterized with regard to genetic relatedness, β‐lactamase, replicon and integron types, antibiotic resistance profiles, and genes encoding virulence factors. In addition, the survival in the environment and on hospital‐associated materials was analysed. CTX‐M‐15 was the most frequent ESBL (78%). Only three (13%) of the AmpC enzymes were harboured on plasmids (CMY‐2, DHA‐1). Independent of plasmid‐mediated beta‐lactamase, IncF plasmids predominated and only class I integrons were detected. The ESBL producers carried more virulence genes (p = 0.04), exhibited a broader resistance phenotype (p = 0.01) and survived significantly longer (p = 0.03) on different materials than the AmpC‐producing isolates. In conclusion, ESBL‐producing isolates had properties which are likely to augment their competitiveness. Apart from antibiotic resistance and virulence factors, extended survival in the environment could be a selective trait for successful ESBL‐producing E. coli strains.     

PDX1 ‐MODY and dorsal pancreatic agenesis: New phenotype of a rare disease

Maturity‐Onset Diabetes of the Young (MODY) type 4 or PDX1 ‐MODY is a rare form of monogenic diabetes caused by heterozygous variants in PDX1 . Pancreatic developmental anomalies related to PDX1 are reported only in neonatal diabetes cases. Here, we describe dorsal pancreatic agenesis in 2 patients with PDX1 ‐MODY. The proband presented with diabetes since 14 years of age and maintained regular glycemic control with low doses of basal insulin and detectable C‐peptide levels after 38 years with diabetes. A diagnosis of MODY was suspected. Targeted next‐generation sequencing identified a heterozygous variant in PDX1 : c.188delC/p.Pro63Argfs*60. Computed tomography revealed caudal pancreatic agenesis. Low fecal elastase indicated exocrine insufficiency. His son had impaired glucose tolerance, presented similar pancreatic agenesis, and harbored the same allelic variant. The unusual presentation in this Brazilian family enabled expansion upon a rare disease phenotype, demonstrating the possibility of detecting pancreatic malformation even in cases of PDX1 ‐related diabetes diagnosed after the first year of life. This finding can improve the management of MODY4 patients, leading to precocious investigation of pancreatic dysgenesis and exocrine dysfunction.     

Expression of miR‐155 and miR‐126 in situ in cutaneous T‐cell lymphoma

Recently, miR‐155 has been implicated in cutaneous T‐cell lymphoma (CTCL). Thus, elevated levels of miR‐155 were observed in skin lesions from CTCL patients as judged from qPCR and micro‐array analysis and aberrant, high miR‐155 expression was associated with severe disease. Moreover, miR‐155 promoted proliferation of malignant T cells in vitro. Little is, however, known about which cell types express miR‐155 in vivo in CTCL skin lesions. Here, we study miR‐155 expression using in situ hybridization (ISH) with a miR‐155 probe, a negative control (scrambled), and a miR‐126 probe as a positive control in nine patients with mycosis fungoides, the most frequent subtype of CTCL. We provide evidence that both malignant and non‐malignant T cells stain weakly to moderately positive with the miR‐155 probe, but generally negative with the miR‐126 and negative control probes. Reversely, endothelial cells stain positive for miR‐126 and negative for miR‐155 and the control probe. Solitary T cells with a malignant morphology display brighter staining with the miR‐155 probe. Taken together, our findings suggest that both malignant and non‐malignant T cells express miR‐155 in situ in CTCL. Moreover, they indicate heterogeneity in miR‐155 expression among malignant T cells.